Zone 2 Cardio Explained

Zone 2 cardio is all of the rage right now.

Even the biggest meatheads who were previously terrified of cardio are getting on board.

Looking at google trends, there seems to be over double the search volume compared to one year ago (at the time of this writing).

So, my aim with this article is to explain the following:

• What is zone 2 cardio?

• What makes zone 2 so helpful?

• How should you do your zone 2 cardio?

• How much zone 2 cardio should you be doing?

As always, if you have questions you feel went unanswered throughout this article, please feel free to email me at info@FitnessSimplified.org or comment below. I’m always happy to help.

What is ‘zone 2’ cardio?

The most commonly used definition of zone 2 is in the second zone in the 5 zone model of endurance training; which goes as follows:

• Zone 1 = 50-60% Max Heart Rate

• Zone 2 = 60-70% Max Heart Rate

• Zone 3 = 70-80% Max Heart Rate

• Zone 4 = 80-90% Max Heart Rate

• Zone 5 = 90-100% Max Heart Rate

  • Max Heart Rate = 220 - your age (this is an estimation & varies person to person; a max heart rate test is needed to definitively find out your max heart rate)

The purpose of zone 2 in this model is to have you train right beneath your lactate threshold.

Using a simple calculation of 60-70% of max heart rate doesn’t always get you quite there, though.

The accuracy of the given maximum heart rate equation varies, and there is variance person-to-person as to whether or not 60-70% of your max heart rate puts you right beneath your lactate threshold.

To be perfectly accurate would require a lactate threshold test; which would involve some general laboratory equipment.

Nevertheless, being perfectly accurate is something that is only required at the highest levels of endurance training; such as IronMan training.

For all other purposes, using the aforementioned heart rate ranges is more than good enough.

What makes zone 2 cardio so helpful?

Training at a zone 2 intensity tends to be intense enough to elicit aerobic/cardiovascular fitness adaptations; but not intense enough to greatly stress your anaerobic (higher intensity) energy systems.

Generally, training that is done using your higher intensity energy systems tends to be more fatiguing and require greater recovery periods.

So, by spending more time in zone 2, you can provide a greater training stimulus to your aerobic/cardiovascular system without much of an increased recovery need.

What exercises should you use for zone 2?

How easy it is to stay within zone 2 is influenced by which exercise you choose to use for it.

Generally, an exercise will be productive for zone 2 training if it is:

• no (or, low) impact

• no eccentric (no lowering of a weight)

• cyclical (involves repetitive actions)

What are some examples of this?

• bicycle (stationary or on road)

• AirDyne

• SkiErg

• Concept 2 Rower

• Incline treadmill walking

Running can be used for zone 2 training if you have high levels of cardiovascular fitness. If you do not, then you might find your heart rate spiking out of zone 2 while running; no matter how slow you try to go.

Reason being: the higher your cardiovascular fitness, the lower your heart rate at rest or any given rate of work.

If you must use for your zone 2 training but aren’t quite fit enough to run continuously while staying under 70% of your MHR, then the following is what I recommend:

• Use jog/walk intervals

  • There are three ways you can go about doing this:

    • Go by heart rate. Jog until your heart rate hits ~70-75% max heart rate. Then, walk until your heart rate comes down to ~55-60% max heart rate. Have a total work time in mind, and repeat this until you’ve completed the time you aimed to complete.

    • Time intervals. Ideally, you want at least a 2:1 work:walk ratio. This tends to work best for people who are beginners to running.

    • Distance intervals. This works best for people who have a good understand of their abilities on specific distances. With these, I usually keep the walk to 0.25 miles and modify the run interval distance to the person I’m working with.

How much zone 2 cardio should you do?

There’s no possible way for me to answer this question.

Truthfully, the best answer I can give you is: as much as you can reasonably commit to each week.

A not-yet-mentioned caveat to zone 2 training is that it is beneficial WHEN it is done at high volumes. This is the main reason its high recoverability is helpful; it allows you to hit the volumes needed for optimal cardiovascular development.

So, the more you can get in on a weekly basis, the better.

Conclusion

My goal here was to provide you with a ~5-minute read that would leave you feeling supremely competent in what zone 2 cardio is and how to do it. To me, this stuff is important. It clearly is to you too to a degree, otherwise I don’t think you’d be here reading this article right now.

As usual, if you feel you still have questions that were left unanswered, you are welcome to email me at info@FitnessSimplified.org.